Ion heating in collisionless shocks in supernovae and the heliosphere.

Abstract

Collisionless shocks play a role in many astrophysical phenomena, from coronal mass ejections (CMEs) in the heliosphere to supernova remnants. Their role in heating and accelerating particles is well accepted yet the exact mechanism for ion heating is not well understood. Two systems, CMEs and supernova remnants, were examined to determine the heating of heavy ions as they pass through collisionless shocks thus providing a seed population for cosmic ray acceleration processes. Three parameters are examined, the plasma beta, the Mach number of the shock and the magnetic angle of the shock. CMEs heat heavy ions preferentially. This is in contrast to the supernova data which shows less than mass proportional heating. In addition to these studies, heating in astrophysical systems involves neutral atoms. A Monte Carlo model simulated neutral particles as they pass through the shock. Neutrals can create a precursor to the shock additionally heating the plasma. This work uses in situ data from the heliosphere to study astronomical systems because of common shock properties is a unique way to study magnetic components of shocks remotely.